1. Field of the Invention
The present invention relates to a charge circuit for a battery pack including a plurality of batteries connected in series, and more particularly, to cell-balancing for equalizing voltages of the plurality of batteries when the battery pack is charged.
2. Discussion of Related Art
When charging and discharging of batteries that are connected in series are repeated, voltages of the batteries become different due to different lifespan of the batteries. When batteries having different voltages are repeatedly charged and discharged, a battery, the performance of which deteriorates to a higher degree than the other batteries is over-discharged or over-charged and is thus accelerated to deteriorate, thereby lowering the performance of a battery pack including the batteries. For effective use of the battery pack, degrees to which the batteries connected in series are charged/discharged should be controlled to be the same. Generally, to this end, the voltages of the batteries are equalized. This process is referred to as cell-balancing. The present invention suggests a method of satisfying such a need.